/Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/Operations/MeshGeodesicSurfaceTracer.h
NB: the BaryPoint must be a valid point within or on the boundary of the triangle.
total distance of the trace, this may be less than the MaxDist (e.g. in the event the trace encounters a mesh edge)
double TraceMeshFromBaryPoint ( const int32 TriID, const FVector3d & BaryPoint, const FVector3d & RayDir3, double MaxDistance )